Low-temperature hydrocarbon combustion over proton conductor/metal–mixed catalysts

Catalytic combustion of hydrocarbons is a highly active field of research, particularly in relation to the reduction of pollutant emissions from automobiles. In this study, we report on hydrocarbon oxidation at the internal interfaces of a mixed catalyst consisting of Sn0.9In0.1P2O7 and Pt powders. In a gaseous mixture of propane, H2O, and O2, the H2O dissociates into protons, electrons and active oxygen species at anodic interface sites, leading to oxidation of the hydrocarbon to CO2. On the other hand, O2 reacts with protons and electrons to form H2O at cathodic interface sites. As a consequence, local electrochemical cells are formed at the interfaces, and undergo self-discharge. It was shown that the mixed catalyst had a high turnover frequency for Pt, yielding high catalytic activity for Pt contents of as low as 0.1 wt% and an initiation temperature for hydrocarbon oxidation of 150 °C.